{"version":"1.1.0","chapters":[{"startTime":0.0,"title":"Why Heart Rate Formulas Fall Short"},{"startTime":200.79,"title":"What Zone Two Really Means"},{"startTime":405.79,"title":"Inside The Five-Zone System"},{"startTime":710.79,"title":"Building Fitness At Threshold"},{"startTime":925.79,"title":"How We Test: VO2, Ventilation, Lactate"},{"startTime":1215.79,"title":"Case Study: Efficiency Gains Explained"},{"startTime":1505.79,"title":"Field Tests And When To Use Them"},{"startTime":1675.79,"title":"Sport-Specific Heart Rate Zones"},{"startTime":1915.79,"title":"Setting Zones In Your Devices"}]}